The invention relates in general to fire extinguisher and retardant materials, and more particularly, to a cellulosic mulch wetted with liquid that tends to stick in place when applied on trees, buildings or the ground to present a barrier to advancing flames.
It is important to extinguish brush, tree and building fires and to provide effective barriers to the spread of such fires in the form of fire lanes forming a fire resistant area to prevent forest fires and brush fires from spreading over and beyond such barriers. There has been a never ending search for suitable materials with which to effectively fight such fires as fire extinguishers and barriers to the spread of fires. An effective fire extinguisher and barrier material may beneficially include water to take advantage of its cooling and smothering effect. Further, it is important that the fire extinguisher-retardant be quite dense to further aid in heat absorption from the fire. Many fires should also be smothered and the ability to stick to areas being treated is most important; thermal protection given by an insulative cover of foam can be quite effective in isolating combustible material from combustion temperatures and blocking oxygen from such combustible materials.
Water is the most useful substance for extinguishing fires, primarily due to its high heat of vaporization, 2260 kJ/kg, which removes heat from the combustion process. However, water readily runs off surfaces, leaving a coating too thin for heat removal or protection. Moreover, water has not been extremely useful in fighting forest fires, since when dropped from the air, it will often vaporize before reaching the fire. In order to overcome these disadvantages, it is know to use thickeners to increase the viscosity of water, such thickeners including both slurries and organic gels. Among the slurry materials are bentonite, ammonium phosphate and ammonium sulfate, which is particularly useful against forest fires.
Foams are also useful in combatting fires, particularly flammable liquid fires. However, foams are unstable by their nature, and have very low density, requiring replacement in large volumes to compensate for loss by evaporation.